Electronics > Repair
TDS6804B failed to power up repair
pasta2018:
I'm fixing a TDS 6804B.The fault phenomenon is that the oscilloscope does not respond when the startup button is pressed. Sometimes when the power is plugged in, the oscilloscope starts and the fan turns, but the oscilloscope shuts down automatically in about 10 seconds.For now, I only keep P1 REAR PWR distribution plate, symptom does not change.I measured the voltage on P1 according to the service manual, and it was almost 0.I would like to ask if the voltage mentioned in the manual needs to be measured by oscilloscope in operate state, or could it be measured under standby state.Also, how to determine if the fault is due to a power failure or a fault caused elsewhere.
calibrationfixture:
Hi pasta2018,
You also must read this:
https://www.eevblog.com/forum/repair/looking-for-tds6124c-os-restore-cd-(xp)/msg3850442/#msg3850442
Member/Poster noticed discrepancies in the Service Manual. The condition of the MB Battery has some influence about how the Power On/Off Button responds. That was the case with my TDS7404B (B02xxxx, same MB and PPC Board).
Calibrationfixture
pasta2018:
Thank you for your information. I will refer to the voltage value he reported.Now my problem is that the oscilloscope does not turn on, occasionally turn on the power on (lasting for about ten seconds) and then automatically shut down. How to confirm whether the power supply voltage is normal in this state? I want to make sure it's the power supply or something.
coromonadalix:
i would pull out the pc section mobo and test it on a bemch, sure it needs a psu ... you would see about the coin cell battery state, the capacitors state on the board etc ...
and check if they have the famous nvram dying battery ... on the power pc board the board under the pc ...
@ab1033 did a good investigation
pasta2018:
I replaced the CR2032 battery on the motherboard, which uses intel865GLC.It is clean, and no leakage capacitor was found.
PPC board is also relatively new, and its nvram is DS1245-100.
Next, I'm going to take care of the metal interface on the memory module.Because now plug in the power can occasionally start for a while, in most cases plug in the power indicator led on but the oscilloscope does not start.
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